Explosive coating material



Patented Get. 24, 1933 LOSIVE COATING MATERIAL Charles P. Spaeth, Woodbury, N. J., assignor to E. 1. du Pont de Nemours- & Company, Wilmington, DeL, acorporation of Delaware No Drawing. Application November 20, 1931 Serial N0. 576,435

11 Claims. (oi; 52-11) My invention relates to a new and improved coating material for explosive compounds and explosive'ingredients and more particularly to an explosive coating material comprising trimethylol ethyl methane trinitrate.

- In the high explosive industry, it is a frequent practice to use coated ingredients in order to modify and control the physical characteristics .of such ingredients. For example, coated ammonium nitrate has been in use for a great many years. In this case, the ammonium nitrate granules are covered with a thin coating of paraflin, petrolatum, or other suitable material. The object of such coating on the ammonium nitrate is to reduce the tendency of the ammonium nitrate to take up moisture from the surroundingatmosphere, due to the great hygroscopicity of the material. The use of the coating material has brought about many advantages. Similarly other coating materials have been used both for protection against moisture and for other reasons.

-Ammonium nitrate has frequently been coated 'with trinitrotoluene for example, in such manner that the coating not only gave protection against moisture but also increased the sensitiveness of the ammonium nitrate.

One of the objects. of my invention is to bring about a coating of ingredients for explosive compositions by a new and improved material, which is itself an: explosive. Another object is the use of a compound as a coating material for ingreclients of explosive compositions which will reduce their tendency to absorb moisture.

A further object is the use of a compound as a coating material, having itself 'such properties as an explosive that relatively insensitive explosive materials will have increased sensitiveness. A still further object is the use of a compound which, when distributed as a coating on explosives of unduly high sensitiveness, will bring about a desensitizing efiect; Another object is .the use of a compound as a binder in the prepa-' ration of free running granules from a finely divided, non-free running explosive material; or as a binder for holding in intimate contact a mixture of several ingredients used in explosive compositions. Further objects will be apparent as my invention is more fully described hereinafter.

In my copending application, Serial No. 576,434, filed November 20, 1931 I have disclosedthe new chemical compound trimethylol ethyl methane trinitrate which has highly valuable properties ,as an explosive compound. This substance is obtained by the nitration, in any suitable way, of

the trihydroxy compound, trimethylol ethyl methane. The nitrated product has the followingformula:-

CHzNOa CzHs-C-CHzNOz CHzNOa I- have discovered. that trimethylol ethyl methane trinitrate is highly desirableas a coating material for. other ingredients of explosives 'and particularly so for other explosive compounds. Because of its intermediate .degree of sensitiveness, it is adapted for use either as a coating for insensitive materials, in which case it functions as a'sensitizing agent, or as a coating for materials that are so highly sensitive as to be undesirable for use alone, in which case it serves as a desensitizing agent.

As for an example of the use of trimethylol ethyl methane trinitrate as a coating material for insensitive materials, I will cite its use in the coating of ammonium nitrate. Trimethylol ethyl methane trinitrate has the necessary properties for use as a coating ingredient, having as it does a waxy nature and a meltingpoint of about 48 C. As a result of this, it is readily applied as a. surface coating to the granules of ammonium nitrate. While it has all the advantages of parafiin and similar coating materials as a waterproofing agent, trimethylol ethylmethane trinitrate is free from the disadvantages of paraffin. While paraflin has a decided desensitizing efiect ethyl methane trinitr'ate is itself an explosive compound of an intermediate degree of sensitive.

ness so that it both protects ammonium nitr'ate against moisture and increases its sensitiveness. Likewise paraifin', and other of the organic coating materials commonly. used for coating explosive ingredients, are-very deficient in oxygen. Trimethylol ethyl methane trinitrate, however, is only slightly deficient in oxygen, hence considerable more ofthis material may be used as a coating when desirable Without disturbing the balance of oxygfin for complete combustion of the explosive mixture. Trimethylol ethyl methane trinitrate may be used to coat other insensitive ingredients of dynamite, as for example sodium nitrate, potassium nitrate, calcium nitrate, urea nitrate, ammonium perchlorate,.and the like.

Trimethylol ethyl methane trinitrate may also be used to advantage in the coating of explosive materials having too high a degree of sensitiveness for safe use in practice. Trimethylol ethyl methane trinitrate has itself an intermediate degree of sensitiveness so that its use as a coating material confers its own degree of s'ensitiveness on the ingredient coated. An illustration of such 5 use lies in its application as a coating material for compounds adapted for use as primary detonating compounds, as well as materials suitable for use as ignition ingredients in blasting caps, which, however, are undesirably sensitive for use by themselves, as for example hexamethylenetriperox-idediamine, trinitrotriazidobenzene, and

like compounds.

A further illustration of the use of trimethylol ethyl methane trinitrate as a coating ingredient of the second class,.is its'use with pentaerythrite tetranitrate. This compound is used frequently with considerable satisfaction as the filling material for detonating fuse. However, the sensi tiveness of fuses filled with pentaerythrite tetranitrate is undesirably high for use in rough work where the material may be exposed to shock and heavy blows. The coating of the pentaerythrite tetranitrate core of such fuse with trimethylol ethyl methane trinitrate obviates the above dif- \ficulties, and gives a satisfactory fuse material.

It is well known that certain explosive ingredients are prepared insuch a way that they comprise finely divided, non-free running, dusty materials which are inferior as constituents of explosive compositions on account of the difliculty in mixing, loading and packing, and which are dangerous because of the dust hazard. I

find that my new explosive coating material may 4 be used quite successfully in removing these difficulties. Dusty, non-free running materials, when mixed in suitable amounts with trimethylol ethyl methane trinitrate, may be made into granules or pellets of a desirable size, which are free running, non-dusty and suitable-for mixing, .loading, and packing as a constituent of any explosive composition. As examples of this, I may mention nitrostarch, pentaerythrite tetranitrate, cyclotrimethylene trinitramine, tetryl, and like compounds.

451 Likewise, it is often desirable to combine in a more intimately associated form a mixture of I several explosive ingredients. This hasthedesirable feature -of preventing the segregation of a mixture of materials having-varying densities. It has the additional advantage of promoting more rapid and more complete combustion of this mixture, with consequent improvement in explosive propagation. It likewise allows an improved method of governing the size and form of the grains or pellets, with-the result that the properties of the explosive may be modified and im proved. For example, I may bind together. a mixture ofammonium nitrate, sodium nitrate,

and an organic combustible material for use,,

so by itself or with other ingredients; as a blasting explosive. Again it is useful in preparing a mixture suitable as an ignition agent in caps which may comprise, for example, lead sulphocyanate, potassium chlorate, and groundsmokeless powder.

It will be understood that in the use of trimethylol ethyl methane trinitrate as .a coating material for, explosive ingredients and compounds, the thickness of the coating will vary in accordance with the necessities of the case. A

coating should be used of sufiicient thickness so that the desired degree of sensitiveness is obtained for the material coated.

It will be further understood that the coating may be applied in the form of liquid trimethylol ethyl methane trinitrate' at an increased'temperature for example 50-60 C., or the coating material may be dissolved in a suitable solvent or mixture of solvents and applied at room temperature, the solvent or solvents being subsequently removed by evaporation.

While I have described 'my invention in detail' in the foregoing, I wish it to be understood that many variations may be made 'without departure from the spirit of the invention, and'that I do not intend to be limited except as indicated in the following patent claims:

I claim:

I. A new composition of matter comprising an ingredient of an explosive composition coated with trimethylol ethyl methane trinitrate.

2. A new composition of matter comprising an inorganic ingredient of an explosive composition coated with trimethylol ethyl methane trinitrate.

3. A new composition of matter comprising an inorganic explosive salt coated with trimethylol ethyl methane trinitrate.

4. A new composition of matter comprising am- I monium nitrate coated with trimethylol ethyl methane trinitrate.

5 A new composition of matter comprising an organic ingredient of an explosive composition coated with trimethylol ethyl methane trinitrate.

6. A new composition of matter comprising an explosive compound coated with trimethylol ethyl methane trinitrate.

7. A new composition of matter comprising an organic explosive compound coated with trimethylol ethyl methane trinitrate.- I

8. A new, composition of matter comprising hexamethylenetriperoxidediamine coated with trimethylol ethyl methane trinitrate.

9. A new composition of matter comprising an explosive mixture, the ingredients of which are coated with trimethylol ethyl methane trinitrate.

10. An explosive composition comprising a mixture of a sulfocyanate, an oxidizing agent, and a fuel, said ingredients being coated with trimeth- 1 ylol ethyl methane trinitrate.

11. An explosive composition comprising lead sulfocyanate, potassium chlorate, and ground smokeless powder, said ingredients beingcoated with trimethylol ethyl methane trinitrate.

CHARLES P. SPAETH. 

